Sleep is essential to good health. Lack of sleep can lead to, among other things, irritability, difficulty concentrating, increased stress, and in extreme cases, even death. Yet it is common knowledge that many people are sleep deprived. This unhealthy condition can result from many factors such as busy work schedules, stress, lifestyle choices, and an environment that involves physical discomfort, such as one requiring a person to try and sleep in unfamiliar resting positions. Complaints about sleep deprivation due to discomfort are particularly common among persons who must travel long distances in a confined seating space, whether by train, bus, car, plane, etc.
For example, the typical plane passenger may experience anxiety, fatigue, and other unhealthy physiological side effects from the stress of attempting to board a flight on time, environmental conditions inside the cabin (such as pressure, ventilation, relative humidity, noise and vibration), cross-infection from fellow passengers, potentially awkward social exchanges, changes in time zones and meal times, and unnatural seating positions and postures adopted for significant periods during a flight.
Body position and seat comfort in particular play vital roles in the overall traveling experience, since a passenger normally spends most of the duration of travel in a seat. In the case of air travel, for example, many airlines attempt to increase profitability by maximizing the number of seats. Although minimum requirements for aircraft seat spacing may exist, such standards were likely designed to align with goals of safety (being able to evacuate in a certain amount of time, etc.) rather than comfort, and thus seating space is too often very limited. Many airline passengers complain of discomfort while flying and of resulting sleep deprivation and desynchronosis (“jet lag”).
Passengers seated in the central position of a three or more seat row in particular often complain of discomfort on flights, due to a feeling of being surrounded and of not being able to comfortably rest to one side or the other without fear of encroaching the space of another passenger's seat. A seat space next to a window, on the other hand, is often coveted because, among other reasons, it may allow a passenger to rest the head to the side against the wall of an airplane cabin. In addition, since economy class seats often recline only to a limited degree, the force of gravity against the body, head, and arm members is not as neutralized as it is when the body is in the fully-reclined sleeping position that most people are accustomed to when sleeping. Specifically, when a person is in a flat-lying sleeping position, a bedframe and mattress normally counter the downward force of gravity on a person's body, head, and extremities, allowing the person to rest more easily. In addition, most people normally use a pillow to elevate the head over the rest of the body, to provide stabilization so that the force of gravity does not pull down the head to the level of the mattress, and to help prevent the neck, back, and shoulder pain that might otherwise occur.
When a person is trying to sleep in a seated body position, however, the downward pull of gravity and any other forces acting on an individual's head must be opposed by some other force, such as a person's neck and shoulders, and neck and shoulder muscles. The neck and shoulders may not reliably maintain such a state of equilibrium of forces when a person is sleeping, which limitation might cause a person's head to jolt when the body attempts to sleep. Furthermore, a simple headrest such as those sometimes found on the back of a seat, while helpful in providing support to the back of the head, usually do not alone effectively equalize all the vector forces acting on the head in the direction from the side of a head facing toward a shoulder.
Several sleeping aid devices have attempted to provide comfort when a person is in a seated body position by equalizing the forces acting on the head, but such devices all present certain disadvantages. The “U”-shaped travel pillow, for example, is usually not designed for use in seats that already provide special support to the back of the head. Furthermore, the “U”-shaped travel pillow's limiting movement of the head in any direction but forward has been criticized by some for causing neck stiffness, and may also limit the head's movement more than a person prefers. Moreover, given the limited degree that many airplane economy-class seats recline, pillow devices that provide support directly behind the head might further limit the degree of recline.
Possibly to attempt to compensate for these deficiencies, other sleeping aid devices have been designed to limit head movement primarily in the forward direction by providing support directly in front of a head or neck. Yet trying to sleep in such a position with the head tilted forward, or with pressure being applied from the forward direction may be an unnatural and/or unfamiliar sleeping position or experience for some people.
Although less common, a few other sleeping aid devices for use in a body position where a person is seated in a seat having a backrest try to achieve a state of equilibrium of the forces acting on the head by utilizing counterweight mechanisms. These counterweight sleeping aid devices may consist generally of a brace or other type of head and neck support, connected to some type of strap that attaches to the wrists or arms, and are designed specifically for use where the person is seated with the head looking straight forward, with the spine straight and back placed flatly against the seat. Moreover, when using such counterweight devices, the tension between the head and neck brace and the arms is normally essentially in the forward and backward directions, with the other lateral vector forces basically balanced between each side of the body, with each arm symmetrically attached to a strap or the same strap. Thus, if one of the arms were not connected to a strap, or in a position different from the other arm, there may be an imbalance of forces acting on the head. In addition, rather than provide comfort for the arm members, some such straps may need to attach to the arms or wrists, and may encumber the arm members with localized pressure. Furthermore, such head and neck braces may not be particularly comfortable.
Moreover, the aforementioned and other prior art sleeping aid devices designed for use when a person is seated in a seat having a backrest generally maintain the head and neck in a neutral straight forward/back position, yet many people are accustomed to and prefer sleeping on their sides, or with the head turned at least partially to the side. Many people (and apparently more women than men) also sleep on their sides in the fetal position, where the arms and hands are held close to the body. Requiring a person who is accustomed to sleeping on the side or in the fetal position, where there are at least some forces acting on the side of a head from the direction of the shoulder, to try and sleep in a straight-forward alignment with the back and head squarely against a seat and headrest, in addition to all of the other factors that make travel a somewhat unnatural experience for the humans, decreases the likelihood that a passenger will achieve a state of sleep, and may also harm the quality of any sleep that is achieved.
Furthermore, even those who may be accustomed to sleeping in a non-side body position certainly do not sleep with the arm members dangling loosely due to the force of gravity. When a person is in a seated position in a seat, loose arm members that do not have proper assistance for opposing the downward pull of gravity may lead to discomfort and make a sleeping state more difficult to achieve. Although certain prior art sleeping aid devices have attempted to solve this problem, none have used a counterweight mechanism that includes a looping strap that loops across the body and has a width configured to stably and comfortably support the person's forearms crossed thereon.
Thus, there is a need for a sleeping aid device for use when a person is seated in a seat having a backrest that more closely replicates the side position and the vector forces in the direction from the shoulder to the side of a head, to which many people are accustomed while sleeping. There is also a need for such a device that assists in neutralizing the force of gravity on the arm members, for example, by comfortably holding one or both arm members close to the body, which may more closely replicate the fetal position to which some are accustomed.